Cast aluminum wheels have been in use on road vehicles for many years. The light weight and esthetically pleasing qualities of the cast aluminum wheel has made the wheel a desirable option on many mass production vehicles. However, cast aluminum wheels are often cost prohibitive due to the cost of manufacturing. Additionally, cast aluminum wheels do not provide enough mass savings to justify the added cost when fuel efficiency is not achieved.
During production, a cast aluminum wheel requires a significant amount of machining to form the wheel in a desired commercial configuration. A cast aluminum wheel includes a rim portion and a central element having spokes extending radially outwardly between a wheel axis and the rim portion. A typical spoke requires upwards of 80% machining to achieve required dimensional accuracy. Machining typically reforms those portions of the wheel into a desired configuration and providing an anesthetically pleasing finish. However, machining also results in sharp transitional edges between adjacent surfaces, which are known to be a source of initiation of stress fractures. In addition, spokes disposed on the wheel between a rim portion and a central element of the wheel are typically provided with substantial thickness and mass to provide necessary strength and stiffness to the wheel, which is cost prohibitive and contrary to efforts to reduce mass.
Thus, efforts to reduce mass of cast aluminum wheels has proven elusive due to structural fatigue, performance, styling and reduced stiffness, all of which are known defects from a reduction in the mass of the spokes. Therefore, it would be desirable to provide a wheel that has both increased stiffness and reduced mass.